1. Field of the Invention
The present invention generally belongs to the field of space environment technology and relates to measurement of the volume of liquid or solid under microgravity. More particularly, the invention concerns volume measuring apparatus for volume measurement under microgravity applicable even in vacuum surroundings, e.g., on an orbit of an artificial satellite.
2. Related Background Art
The technology about the measurement of the volume of liquid with sound is already known, for example, as described in Japanese Patent Applications Laid-Open No. 08-327429 and No. 07-83730. The known devices described in these applications both are comprised of a container and a pipe communicating with an open space at one end. The measurement is carried out by a method of generating sound by a speaker or the like, collecting the Helmholtz resonant sound induced by spring action of the gas phase in the pipe and container, by a microphone, and calculating the volume of liquid from the resonance frequency of the Helmholtz resonant sound. There are also devices in which two containers are coupled to form a closed space and in which pressure fluctuations are detected to determine the volume of liquid, for example, as described in Japanese Patent Applications Laid-Open No. 06-201433 and No. 06-201434.
For measuring the volume of a liquid or the like in a container placed on an orbit of an artificial satellite, it is, however, first necessary to create a closed space, because the surroundings are a vacuum. The prior arts making use of the Helmholtz resonance had the critical defect that the devices were applicable only in the open space. The prior arts of measuring the volume of liquid or the like by detecting the pressure fluctuations were applicable to the use in the closed space, but had the problem that, because there occurred mixture of gas and liquid under microgravity, a device for controlling it was indispensable.
An object of the present invention is to provide volume measuring apparatus that can be used in the closed space as in the case of the measurement to measure the volume of liquid or solid in a container placed on an orbit of an artificial satellite and that can measure the volume of liquid or solid in a state without mixture with a gas phase, a liquid phase, or a solid phase.
A volume measuring apparatus according to the present invention is an apparatus for measuring volume under microgravity, comprising two or more containers, a pipe coupling the containers to each other, means for separating or fixing a gas phase, a liquid phase, or a solid phase, a pressure fluctuation source, and a pressure fluctuation signal receiver, wherein the separating or fixing means, pressure fluctuation source, and pressure fluctuation signal receiver are placed in the containers, and wherein the pressure fluctuation source and the pressure variation signal receiver are connected to a signal analyzing unit.
Another volume measuring apparatus according to the present invention is an apparatus for measuring volume under microgravity, comprising two or more containers, a pipe coupling the containers to each other, means for separating a gas phase or a liquid phase, a sound source, a sound receiver, a thermometer, and a pressure gage, wherein the separating means, sound source, sound receiver, thermometer, and pressure gage are placed in the containers, and wherein the sound source is connected to a signal generator, the sound receiver is connected to a signal processor, and the signal processor, thermometer, and pressure gage are connected to a volume analyzer.
Still another volume measuring apparatus according to the present invention is an apparatus for measuring volume under microgravity, comprising two or more containers, a pipe coupling the containers to each other, means for separating a gas phase or a liquid phase, a pressure fluctuation source, a pressure gage, and a thermometer, wherein the separating means, pressure fluctuation source, pressure gage, and thermometer are placed in the containers, and wherein the pressure fluctuation source is connected to a signal generator, and the pressure gage and thermometer are connected to a signal analyzer.
The volume measuring apparatus according to the present invention is also characterized in that means for fixing a solid phase is provided in the containers.
The volume measuring apparatus according to the present invention is also characterized in that a container is partitioned into two or more compartments by a partition and the compartments are connected to each other by a pipe.